The present invention relates to a car side video assisted system, especially to a car side video assisted system that uses light signals as activation signal sources to select and activate one of at least two car side cameras. Moreover, a light signal interpretation processor is arranged at a video signal source switch processor. Thus signal interpretation is started after a preset critical time, continued for a period of time, and then interpretation result is output.
Car side video assisted systems have gradually become essential safety equipment of vehicles. Generally, a plurality of cameras is arranged at different positions of a car. When drivers are reversing cars, turning left or turning right, one of the cameras is activated synchronously and correspondingly. For example, the rear side camera is activated while the car is reversing. The left side camera or the right side camera is activated when the driver is turning left or turning right so as to capture images at corresponding car side and output the car side images captured by the corresponding camera to a screen of a display device. At least one picture is shown on the screen. Take a Taiwanese car model such as Luxgen as an example. The car side video assisted system show images at the front side, the rear side, the left side, and the right side of the car while reversing the car. While turning left or right, images at the left side or the right side of the car are displayed on the screen. Thus the driving safety during reversing, parking, turning left and turning right is improved.
Techniques related to car side video assist systems usually uses vehicle signals such as range signals or indicator light signals as activation signal sources. That means the reverse gear shift or switching of the indicator lights such as to the left turn switch or the right turn switch is considered as an activation mode of light signals. Thus corresponding cameras at car sides are respectively activated by the activation signal sources to have pictures shown on the screen and seen by the driver. However, the car side video assist systems with such activation mode need to be connected to gear shifts or switches of indicator lights while being installed. Thus the systems are built in cars when the cars are out of the factory. It's difficult to install the video assist systems after the car becoming out of the factory. The installation of the video assist systems is in special car service and repair plants. This is not good for promotion and prevalence of the car side video assist systems. Moreover, the installation cost is also increased due to difficulties in installation. The integrity of internal equipment or car body may be also damaged.
If light signals such as reverse signals, left turn signals or right turn signals are used as activation signal sources to activate corresponding cameras at car sides respectively to replace the vehicle signals used before. Yet the car side video assist system with such activation mode still has following problems while in use.
First the light signals of cars generally include reverse signals, left/right turn signals and warning signals. The warning signal is formed by the left turn signal and the right turn signal activated at the same time (synchronous light signals). But circuit of the left light signal and circuit of the right turn signal are two separated circuit. Thus strictly speaking, the left turn signal and the right turn signal are not activated synchronously. There is a time difference between the left turn signal and the right turn signal when the driver switched to the warning signal. The time difference varies according to different design of car models or car bodies, generally ranging from 0.15 second to 0.25 second or shorter. In consideration of the time difference, one of the left and the right turn signals such as the left turn signal is activated first (the time difference is no longer than 0.15-0.25 second) when the driver switches the light signal to the warning signal. At this moment, the video signal source switch processor uses the left turn signal as the activation signal source so as to activate the left side camera correspondingly for capturing images on the left side of the car and showing the left side images on the screen. Then the right turn signal is also on. Now the video signal source switch processor takes the right turn signal as the activation signal source so that the right side camera is activated correspondingly and the right side images are captured and displayed on the screen. This causes quick switch between the image taken from the car left side and the image captured from the car right side on the screen and the driver is unable to see the images clearly. Or the left turn signal is activated first while the right turn signal is activated later (the time difference is no longer than 0.15-0.25 second). Then the video signal source switch processor uses the left turn signal as the activation signal source so as to activate the left side camera correspondingly for capturing images on the left side of the car, outputting and displaying the left side images on the screen. When the right turn signal is activated, the video signal source switch processor still takes the left turn signal as the activation signal source to activate the left side camera correspondingly for capturing, outputting and showing the left side images on the screen. The left side images continue staying on the screen. That means the video signal source switch processor can't accurately use the warning signal as the activation signal source to activate the corresponding cameras preset. For example, it is originally set to activate multiple cameras when the warning signal is activated. The multiple cameras including at least three cameras—the left side camera, the right side camera and the rear side camera for capturing images at three sides of the car and outputting the images to form three sub-pictures on the screen. The images on the left side, the right side and the rear side of the car are displayed on the screen at the same time. Thus the video signal source switch processor is unable to provide the preset functions and the activation accuracy is affected. Therefore the efficiency of the car side video assist system is reduced.
Moreover, no matter the light signals of cars including reverse signals, left/right turn signals and warning signals are activated or enabled, noises occur at the circuit. For example, the noises are generated when the car battery power and other electrical equipment are used at the same time. The duration of the noise is usually shorter than that of the light signals, just a few milliseconds such as 8 milliseconds (0.008 s). But misinterpretation is still easy to occur in the car side video assist system when the noises and the light signals are mixed with each other. Thus the activation accuracy is affected.
Furthermore, the car side video assist system available now, including the car side video assist system using vehicle signals as activation signal sources, basically doesn't take the priority of the light signals into consideration. The so-called priority means which car side camera is activated and images at the corresponding side of the car are first displayed on the screen of the display device are determined according to the importance of the activation light signals. Thus the images are divided into substitutive images and non-substitutive images. The driver usually turns on light signals according to his driving habits. The action/event of each light signal activated independently has certain meaning and respective importance. Thus the action/event can be substitutive and non-substitutive. For example, the importance of the action of the warning light is larger than that of the turning light while the car is broken down or the driver is parking on roadside. Thus the action of the turning light can be immediately replaced by the action of the warning light. That means the images displayed correspondingly to the action of the turning light are substituted by the images displayed correspondingly to the action of the warning light while the images displayed correspondingly to the action of the warning light are non-substituted by the images displayed correspondingly to the action of the turning light. The importance of the action of the turning light is larger than that of the reversing. Thus the action of the reversing light can be immediately replaced by the action of the warning light. That means the images displayed correspondingly to the action of the reversing light are substituted by the images displayed correspondingly to the action of the turning light while the images displayed correspondingly to the action of the turning light are non-substituted by the images displayed correspondingly to the action of the reversing light. The left turn light and the right turn, light are of the same importance. Thus images displayed correspondingly to the action of a previous turning light are replaced by images displayed correspondingly to a new turning light. If the car side images on the screen of the car side video assist system can be displayed according to the preset priority logic mentioned above, this not only matches driver's driving habits but also improves the efficiency of the car side video assist system. However, the car side video assist system available now doesn't take the above priority into consideration. While in use, images at the rear side, left side or right side of the car are displayed on the screen during car reversing, left turn or right turn. Once there is an accidental event, the images are unable to be switched immediately for satisfying the driver's needs. For example, the driver needs to turn on the warning light when the left/right turn light is on under certain conditions (such as the driver finds the parking space after turning the car and intends to get the space). Yet the image on the screen is unable to be switched from the left/right side image to the image corresponding to the action of the warning light with higher priority along with the warning light. That means the action of the warning light can't replace the action of the turning light. Under another condition, the driver needs to see the left side image while reversing the car (without affecting other cars) but the image is unable to be switched from the reversing image to the image corresponding to the left turn light immediately along with the left turn light. That means the action of the turning light can't replace the action of the reversing light.
In addition, the screen of the car side video assist system available now only shows the action of the driver at the moment such as reversing the car, activation of the left turn signal or the right turn signal. Once the driver stop the above action, the image on the screen disappears synchronously. The video assist system is unable to automatically switch to show useful pictures on the screen for driver's reference according to the driver's driving habits. Take the condition of parking the car or driving the car out of roadside parking space as an example. The roadside parking or driving the car out is unable to be done at once. That means the driver can't drive the car into or out of the narrow parking space just by one-time car reversing. The driver needs to reverse the car and then drive the car forward several times. Yet the car side video assist system used now only shows images on the rear side of the car while the driver reversing the car. Once the driver puts the car into other gear, the image on the screen disappears and there is no other useful images shown on the screen for the driver's reference during the parking process. For example, when the car is driving forward, the driver doesn't know whether there is an object (such as mudguard of a front car) in front of or under the car. Some careful drivers may turn on the warning signal during the parking process for increasing the driving safety. The car side video assist system available now has not take such condition into consideration so that the system doesn't work under the condition.
Thus there is a need to develop a car side video assist system that is easy to be installed on various car bodies for improving both the consumer acceptance and the market acceptance. Moreover, the efficiency of the car side video assist system is improved and misinterpretation caused by noises can be avoided for increasing the interpretation accuracy.